Adhesive bonding means for mounting glass sheets in a window aperture

ABSTRACT

The invention relates to the mounting of a glass sheet, particularly a windshield, on the recessed surface in the sheet metal of the frame of an automobile body, by means of an adhesive strip. According to the invention, the strip is applied simultaneously by co-extrusion with a flexible wire or filament of high tensile strength, said application being over the entire periphery of the glass sheet. If it is found necessary to remove the glass sheet, the wire serves as a cutting element to cut the strip in two.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The subject of the present invention is a method for adhesively bondingglass sheets in a window aperture, particularly in a window aperture ofthe body of an automobile. In particular, a mounting method is proposedwhich enables the glass sheet to be removed easily if it is foundnecessary to do so. The invention is also directed to a glass sheetsuited for use in said such a method, and a device (in the nature of atool) for carrying out the method.

In the following description, reference will be made exclusively toautomobile windshields; however, it should be understood that theinvention may be applied to rear windows or any other windows of anautomobile, as well as to the installation of windows in a building orvessel.

Currently there is a trend toward direct mounting of automobile windowsonto the body, particularly in the case of front (windshields) and rearwindows. A technique of this type is known whereby a strip of adhesiveis deposited on the reverse side of the glass sheet, whereby a seal isformed between the two sides of the sheet, in the form of an opaquecoating deposited along the periphery of the sheet. Such a system isdescribed, for example, in German No. OS 20 38 016. After being appliedin a plastic state, the strip of adhesive material hardens to producethe joint between the glass sheet and the window aperture in theautomobile body.

If subsequently there is occasion to replace a glass sheet installed inthis manner, a problem is presented. The adhesive strip must bedetached, but there is difficulty in gaining access to it. There is astrong risk that the tools which must be employed for this purpose willdamage the face of the glass sheet at its periphery. The hardness of theadhesive strip after polymerization greatly reduces the possibility ofmanipulating the glass sheet within the window aperture, and it becomesa laborious operation to cut or gouge the glass sheet free. It has beenproposed to release the glass sheet by means of a tool in the form of awire or the like, whereby the wire is pushed transversely into theadhesive strip and then longitudinally through said strip at the edgesof the glass sheet.

SUMMARY OF THE INVENTION

It is an object of the invention to further improve the mounting of aglass sheet in a window aperture by direct adhesive bonding, by means ofa mounting method which permits the glass sheet to be removed quicklyand easily.

Toward this end, the invention proposes a method of mounting a glasssheet in a window aperture by adhesive bonding, whereby first an opaquefacing is applied along the periphery of the glass sheet along with, ifnecessary or desirable, one or more primary adhesion-promoting layers,and then a shaped adhesive strip in a plastic state is applied on top ofthis, which strip may or may not effect direct adhesive bonding of theglass sheet to the window aperture, i.e., it may be an intermediaryadhesive layer, and the glass sheet is affixed to the window aperturewith the aid of said adhesive strip or an additional adhesive strip.According to the invention, a flexible wire or filament, in particular ametallic wire of apreciable tensile strength, is applied simultaneoluslywith, and in the same direction as, the shaped adhesive strip. The wiremay be disposed within the shaped strip itself or in proximity to italong its periphery and facing the body of the glass sheet.

According to the invention the flexible wire has the following function:If it is necessary for the adhesive strip to be cut, the wire serves asa tool for cutting it in two. To perform this cutting, the wire is freedat a predetermined location and is grasped at one end, then is caused topass through the shaped strip of adhesive progressively along theperiphery of the glass sheet.

According to a particularly advantageous embodiment of the invention,before the windshield is mounted in the window opening of the vehiclebody and preferably after the windshield is fabricated, a shaped stripwith an incorporated flexible wire may be deposited by extrusion alongthe edge region (margin) of the glass sheet. Later, at the time mountingis to occur, this strip, which has by now hardened, serves as anintermediary between the glass and an adhesive strip proper, i.e.,another strip, which is to accomplish the ultimate adhesive bonding tothe frame, which latter strip is deposited on top of the first strip.This embodiment of the invention is particularly advantageous, since astrip applied in the factory where the glass is manufactured maysimultaneously serve as a spacer between glass sheets during theirhandling and shipping, and may protect their edges.

According to a supplementary feature of the invention, it is possible toutilize nearly all the tension force exerted on the wire to cut theadhesive strip in two, if a flexible wire is employed which adheres onlyweakly to the adhesive strip or which is surrounded by a sheathing orcoated by a coating which reduces that adhesion. Particularly suitablecoating materials include, e.g., separating agents based on wax or onsilicone. In this way only a small amount of power is required to detachthe wire.

In order to obtain the flexibility required for introducing the wireinto a very viscous adhesive mass, it is advantageous in principle toemploy a wire comprised of organic filaments having high tensilestrength. Examples of such wires are nylon, Perlon, or preferably thosebased on poly-p-phenylenediamineterephthalamide. Such wires or filamentsbasically have a similar tensile strength to steel.

If necessary or desirable, a fine metallic wire may be wound helicallyaround the above-described wire or thread, as an aid in cutting theadhesive strip. With such a structure, the ends of the metallic wire maybe connected to a current source and thereby may be heated sufficientlyto facilitate the cutting.

Stranded wires may also have sufficient flexibility, and may find use asthe subject cutting wire.

The invention also relates to a glass sheet for an automobile, whichsheet is particularly advantageous for use with a particular embodimentof the inventive method. Such a glass sheet is noteworthy in that at thetime of mounting of the sheet in the window aperture the sheet isalready covered along its edges with an adhesive strip, i.e., a stripforming part of the total gasket structure which has hardened, whichhardened strip serves as an intermediate between the glass sheet and asupplementary adhesive strip which is brought into contact with a recessin the window aperture of the vehicle body. A flexible wire or the likehaving high tensile strenght is disposed in this (supplementary) part ofthe strip, in particular along the edge of the part directed toward thebody of the glass sheet, and at least one of the ends of the wire isdisposed on the end face of the glass sheet.

Finally, the invention also relates to a device for carrying out themethod of the invention or for fabricating the inventive glass sheet,said device comprising, in its basic features, an extrusion nozzlehaving a shaped orifice, for depositing a highly viscous adhesive massand provided with a conduit which guides a flexible wire or filament upto the shaped orifice. The wire is unwound from a supply spool and runsthence along a generatrix of the nozzle.

According to a variant of the invention, the cutting wire may bedisposed in another profiled strip which is in addition to the unitaryor layered, main strip as above described.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the invention will becomeapparent in the course of the following description of variousembodiments of the invention with the aid of the attached FIGS. 1 to 10.

FIG. 1 shows a cross-section of a peripheral region of a windshieldformed and held together according to the simplest embodiment of theinvention, in a window aperture of a vehicle body;

FIG. 2 is an elevation view of the windshield of FIG. 1, with a devicefor withdrawing the wire which wire is embedded in the adhesive strip;

FIG. 3 shows a cross-section of a peripheral region of a glass sheetmounted with a shaped strip serving as an intermediate for the adhesivestrip which provides the ultimate adhesive bond;

FIG. 4 shows a cross-section of another embodiment of a glass sheetmounting according to the invention;

FIG. 5 shows an embodiment in which the wire is disposed in asupplementary profiled strip;

FIG. 6 shows a device for simultaneously depositing an adhesive stripand a wire to the surface of a glass sheet; and

FIGS. 7 to 10 illustrate the sequence of steps in the method forsimultaneously depositing the adhesive strip and the wire with the aidof the device of FIG. 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

For convenience in illustration, the glass sheet 1 is shown as a simpletype, but obviously any type of glass sheet can be mounted in anautomobile body in the manner described. The sealing and attaching meansproposed according to the invention are basically independent of thetype of glass sheet employed. At the same time, the invention isparticularly applicable to laminated glass windshields, due to the factthat this is the type of windshield currently in general use.

The windshield glass 1 is furnished with a facing 4 comprised of anopaque material, running over the entire periphery of the side of theglass facing the recessed surface 2 of theframe proper 3 of the body(FIG. 1). A strip of adhesive material 5 is deposited on the facing 4. Awire 6 is disposed in the interior of strip 5. The facing 4 may becomprised of porcelain enamel or a polymer. It plays a decorative rolewhile also hiding the covered region of adhesive from external viewthrough the glass. Further, it protects the adhesive strip 5 from UVradiation, and it may also be a means for improved adhesion of theadhesive strip 5 to the surface of the glass. A suitable ceramic pastefor preparing the porcelain enamel may be chosen from among thosecommercially available, taking into account these factors. Inparticular, according to one method, enamel pastes are applied to theglass rsurface, e.g., by serigraphy, and these are fired in the courseof the other required high temperature operations (such as the curvingof the glass).

The glass sheet is adhesively bonded to the recessed sheet metal surface2 of the body of the vehicle by the adhesive strip 5, which may becomprised, e.g., of butyl rubber or polyurethane, particularly apolyurethane of a composition which hardens in the presence of moisture.

The adhesive strip is applied to the surface of the facing 4 by means ofa suitable extrusion nozzle. In this connection a device is employedwhich will be described in detail with the aid of FIGS. 6 to 10. Withthis device, the strip 5 and the cutting wire 6 are appliedsimultaneously.

The disposition of the flexible cutting wire 6 within the cross-sectionof the strip 5 is chosen such that, after application of the strip, thewire is disposed within the strip near the side 7 which faces the bodyof the glass sheet and on the surface of the facing 4.

The following is the method for applying the sealing means comprised ofthe strip and the wire, onto the glass, and for installing the glass inthe window aperture of the vehicle body: Before the adhesive strip isapplied, one end 9 of the wire is extended out and is bent onto the endface 11 of the glass sheet. Then the adhesive strip 5 incorporating thewire 6 is extruded and deposited onto the edge regions (margins) of theglass sheet. When the strip has been deposited in one complete circuitaround the periphery of the glass sheet, the supply of adhesive from theextrusion nozzle is interrupted. An additional 10 cm of wire iswithdrawn, and the end 10 thereof is bent around in generally the samemanner as was done with the other end 9 (FIG. 2), whereby the wire isbent onto the end face 11 of the glass sheet after being passed throughor over the adhesive strip. Only when this has been done is the glasssheet thus prepared placed against the side 3' of the recess, and ispressed against the recessed surface 2 of the sheet metal of the body.The ends 9 and 10 of the wire are then disposed in the space between theside 3' of the recess and the end face 11 of the windshield.

To remove the windshield, the following procedure may be employed, whichis described with reference to FIG. 2: One of the ends 9 or 10 of thewire is pulled out of the space between the peripheral end face 11 ofthe glass sheet and the side 3' of the recess, and the strong tension isapplied to said wire, whereby the adhesive strip 5 is sliced in two,whereupon the windshield can be easily removed. As shown in FIG. 2, thewire may be pulled with the aid of a drill device 14 with a controllablespeed of rotation. In particular, a rod 16 having a transverse bore 17transverse to the axis of rotation of the tool is mounted in the chuck15 of the drill device. The end 9 of the wire is fixed in the said bore,and the wire is wound onto the rod by slow rotation of the rod. The wirecan be withdrawn from the adhesive strip without difficulty.

In the embodiment shown in FIG. 3, the windshield 1 is again furnishedwith an opaque facing 4, e.g., of enamel. A shaped strip 20, containingthe wire 6, is applied to this facing and adheres to the facing. Thefinal disposition of the wire 6 is at the side 7 of the strip 20 whichfaces the mass of the glass sheet. According to the invention, the stripis applied on-site at the facility where the windshield is fabricated,and at the time when it is fabricated. It is extruded by basically thesame method as used for the example of FIG. 1 (described above), withthe appropriate extrusion nozzle. The intermediate shaped strip 20hardens quickly after application, and thus protects the edges of theglass during shipping and storage. It is comprised of a plastic materialwhich is compatible with and forms an air-tight joint with the adhesivestrip 21 which strip 21 forms the ultimate adhesive bond. Strip 21 isapplied either onto strip 20 or onto the recessed surface in the sheetmetal of the body of the vehicle, at a time just prior to the pressingof the glass sheet onto the recessed surface 2 in the sheet metal of thebody. Preferably the materials of which the strips 20 and 21 arecomprised are plastics of the same type. In any event, the material ofstrip 20 should be slightly harder at the time of insertion of the glassinto the window aperture than that of strip 21. Strip 20 is profiled onits side adjacent to adhesive strip 21, and further includes tonguemembers, i.e., "barrier projections" 23 directed toward the recessedsurface 2 of the sheet metal and away from the glass sheet, so as tolimit any spreading of strip 21. Strip 21 is not as thick as it would beif it were required to be the sole adhesive bonding agent of the glasssheet. Therefore it hardens more rapidly, and the time required forsecure installation is thereby reduced. The strength and stability ofthe junction between the windshield and the vehicle body is increased asthe adhesive material of the strip 21 undergoes hardening.

If the wire is disposed directly against the glass surface without theintermediate of the opaque facing 4, it may have a decorative function.If desired it may be colored or be given any other ornamental feature.

FIG. 4 shows an exemplary embodiment of a mounting assembly includingsupplementary decorative seals. Here a profiled intermediate strip 25 isdeposited by extrusion at the same time as a wire 6, onto an opaquefacing 4. The sides 26 of the strip are recessed toward the rear, i.e.,as the glass is approached along the normal to the glass surface, and inthese regions on both sides the strip is penetrated by parts ofsupplementary profiled strips. One such strip 28 is inserted on the sidefacing the interior of the glass sheet, and is supplied withornamentation on a band 29 on its face adjoining the surface of theglass. On the opposite side, a gasket 30 is inserted, filling the emptyspace between the peripheral end face 11 of the glass sheet and the side3' of the aperture recess. An adhesive strip 21 bonds the glass sheet inplace in the window aperture, by adhering to the recessed surface 2 ofthe sheet metal of the body on the one hand and to the strip 25 on theother.

In the embodiment of FIG. 5, a wire 32 is embedded in a supplementaryprofiled strip 33 adhesively bonded to the internal side of an opaquefacing 4. Profiled strip 33 includes a barrier projection 34 which actsas a detent and enables the limitation of any spreading of the adhesivestrip 35 which is deposited subsequently onto the remaining exposedsurface of the facing 4. The strips 35 and 33 may be appliedsimultaneously (one behind the other) or in sequence. The two free endsof the cutting element 32 are bent such that after the glass sheet 1 ismounted in the window aperture said ends may be disposed in the space 38between the end face of the strip 35 and the frame 3 and 3' of thewindow aperture. The still unoccupied space between the frame (3, 3')and the peripheral end face 11 of the windshield is filled by anairtight gasket 40. When there is occasion to remove the windshield, thestrip 35 is cut as described in connection with FIG. 2.

FIG. 6 shows a device for simultaneously depositing an adhesive strip 5and a flexible cutting wire 6 onto the edge region (margin) of a glasssheet 1. The extrusion nozzle proper 42, comprises a segment of a squareor rectangular conduit which has an upward projection in the form of atubular segment 43. This tubular segment is connected in a manner notshown to guide eyelets 54 and 55, and thence wire is fed to conduit 46.The guide eyelets, the pair of feed reels 56, and the drive motor 57 forthe reels are affixed to the conduit tubular segment 43. The motor 57 iscontrolled such that the flexible wire is advanced at the same speed atwhich the nozzle moves in direction F. In order to reduce frictionbetween the wire and the internal wall of conduit 46, pressurized air isinjected at the top of conduit 46 via a small tube 58. The air alsosimultaneously aids in the transportation of the wire in the conduit.

The advancement of the wire 6 and the movement of the nozzle arecoordinated so that at the beginning and end of a deposition cycle ofthe adhesive strip the wire is unwound for a certain length withoutaccompanying adhesive material, thereby providing the two end segments 9and 10 which, when the glass sheet has been mounted in the windowaperture, comprise the free ends which may be used to cut the adjesivestrip in two. The respective movements of the strip and the wire areillustrated in detail in FIGS. 7 to 10.

Before beginning the deposition of the strip and wire, i.e., in theposition illustrated in FIG. 7, the nozzle 42 is disposed above theglass sheet 1 and slightly to the outside, i.e., beyond the lateraledge. A length of wire of about 10 cm is unwound as the motor 57 isstarted and air is injected into conduit 46. Then the wire is grippedwith a clamp 60, and the nozzle 42 and clamp 60 are moved alongsimultaneously in the direction of arrow a, i.e., in a directionperpendicular to the end face of the glass sheet, so that material,i.e., adhesive and wire, can be supplied above the edge region (margin)of the glass sheet. The clamp is lowered to the glass sheet (arrow b),where it holds the wire in place on the surface of the glass. Meanwhilethe nozzle 42 is moved slightly in direction c, is lowered onto theglass sheet, and begins movement in direction F.

A short time after the movement of nozzle 42 is begun, the positions ofthe various parts of the device are as shown in FIG. 8. The wire 6 isstill held in place by the clamp 60. After the movement of the nozzle 42is begun, the pressure in the feed system for the adhesive material isincreased, and the adhesive strip 5 takes on a cross-sectional shape 62which is temporarily sloped but which then quickly attains the finaldesired thickness. The clamp 60 is opened and releases the wire 6,whereupon the clamp is raised back to its original position. The nozzle42 continues along its path along the edge region (margin) of the glasssheet.

FIG. 9 illustrates the final phase in the deposition of the adhesivestrip. After the nozzle has made an entire circuit around the glass andreached the region 62 corresponding to the beginning of the deposition,the pressure of the adhesive material is decreased, whereby the two endsof the strip are joined with no overlapping. Then the feed of adhesivematerial is completely stopped, with the nozzle in its final position,whence it is raised in direction e, is rotated 180° around its verticalaxis, and is moved in direction g transversely to the edge of the glasssheet and toward the region exterior thereto. During this time the wirecontinues to be unwound, forming at the exterior of the glass sheet abend or loop which will become the end segment 10 of the wire as shownin FIG. 10. The wire is then grasped by the clamp 60 and is cut by acutter which operates simultaneously with the clamp. This concludes thedeposition cycle. The glass sheet thus prepared is removed.

In a more advantageous variant of the invention, the nozzle 42 is guidedby the arms of a robot. In this case all the movements are controlledfrom a central control unit, including the movements related to theadvancement of the wire feed and the movements of the clamp 60 and thecutter 64.

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:
 1. A method for adhesively bonding a glass sheetin an aperture, comprising the steps of:applying an opaque facing alongat least a portion of the periphery of said glass sheet; forming a firstelongated shaped adhesive strip in a plastic state on said opaquefacing; simultaneously providing on said opaque facing a flexiblefilament formed of a material having high tensile strength and having alength extending substantially parallel to said adhesive strip;permitting said adhesive strip to cure; providing a second adhesivestrip on said first adhesive strip; positioning said glass sheet in saidaperture with said glass sheet periphery being positioned adjacent aframe of said aperture and with said elongated first and second adhesivestrip and said filament being positioned between said periphery and saidframe; and permitting said adhesive strip to cure, whereby said glasssheet is bonded to said frame.
 2. The method of claim 1 wherein saidfilament is positioned between said opaque facing and said firstadhesive strip.
 3. The method of claim 2 wherein said filament ispositioned directly on said opaque facing.
 4. The method of claim 1including, prior to said positioning step, the step of bending at leastone end of said filament out of parallel relationship with said adhesivestrip and positioning said one end laterally beyond said periphery ofsaid glass sheet, whereby said at least one end is located in a spacebetween said periphery and said frame.
 5. The method of claim 4 whereinafter said adhesive strip has been applied over the entire periphery ofthe glass sheet, another end of the flexible wire is laterally bentbeyond said periphery of the glass sheet while being caused to passthrough or over the adhesive strip, whereby said another end is disposedin said space between said periphery and said frame.
 6. The method ofclaim 1 wherein said filament is metallic and has a surface whichadheres weakly to the adhesive strip.
 7. The method of claim 1 whereinsaid filament is in the form of a stranded wire having high tensilestrength.
 8. The method of claim 1 wherein said filament is in the formof a thread comprised of organic fibers, said fibers having high tensilestrength.
 9. The method of claim 8 wherein said filament is comprised offibers based on poly-p-phenylenediamine-terephthalamide.
 10. A glasssheet for an automobile, intended to be directly adhesively bonded tothe automobile body, said sheet comprising:a sheet element covered alongan edge region with a hardened adhesive strip; and a flexible filamenthaving high tensile strength disposed in, and parallel to the length of,the said hardened adhesive strip along said edge of the said strip, saidfilament being positioned between said glass sheet element and saidadhesive strip, wherein at least one of the ends of said filament isdisposed laterally beyond an edge of glass sheet element.
 11. A devicefor applying an adhesive strip to a sheet, said device comprising:anextrusion nozzle having a shaped orifice; means for supplying a viscousadhesive material under pressure to said nozzle, whereby an adhesivestrip may be extruded from said orifice; means associated with saidnozzle for supplying a flexible filament; and guide means associatedwith said nozzle for guiding said filament to said orifice.
 12. Thedevice of claim 11, wherein said means for guiding said flexiblefilament comprises a conduit disposed outside of the nozzle, on a sideopposite to said shaped orifice and an aperture in the wall of thenozzle and adjacent an end of said conduit.
 13. The device of claim 12including means for moving said nozzle, wherein said means for supplyingsaid filament includes driven advancement reels which advance theflexible filament at a speed which coincides with that of said nozzle,wherein said reels are disposed upstream of said conduit.
 14. The deviceof claim 12 including an air supply tube connected to a pressure source,and which has an outlet in said conduit.
 15. The device of claim 11including a clamp for grasping a free end of said filament, which clampis movable in a direction perpendicular to an end face of said sheet.